There is a need for recoding a decoded video signal. In this case, it is known that, if an encoder of a latter stage performs coding by using a coding parameter that has been used by an encoder of a former stage, little or no image quality deterioration occur.
Then, when there is the need for recoding the decoded video signal, coding information (information of the coding parameter) that has been used by the encoder of the former stage is superimposed on the decoded video signal.
For realizing this processing, in the Mole format of the conventional MPEG-2 (SMPTE standard), processing is performed such that, for each macro block, coding information of the macro block is embedded into 1 bit of LSB of the color-difference component of the video signal at a corresponding timing (refer to non-patent document 1, for example).
The existing video transmission interface such as HD-SDI and SD-SDI performs 10-bit transmission. So, 2 bits can be used when transmitting an 8-bit video signal. Thus, in the Mole format of the conventional MPEG-2 (SMPTE standard), a plane of 1 bit (1 bit of LSB) of the 2 bits is used, so that the coding information of the macroblock is embedded into 16×16=256 bits of the plane.
According to this configuration, the coding information of MPEG-2 can be transmitted together with the video signal at a rate no more than 256 bits/macroblock.    [Non-patent document 1] SMPTE 319M “Transporting MPEG-2 Recoding Information through 4:2:2 Component Digital Interfaces” SMPTE Journal, February 2000.